Quasi-periodic, propagating fast mode magnetosonic waves in the corona weredifficult to observe in the past due to relatively low instrument cadences. Wereport here evidence of such waves directly imaged in EUV by the new SDO AIAinstrument. In the 2010 August 1 C3.2 flare/CME event, we find arc-shaped wavetrains of 1-5% intensity variations (lifetime ~200 s) that emanate near theflare kernel and propagate outward up to ~400 Mm along a funnel of coronalloops. Sinusoidal fits to a typical wave train indicate a phase velocity of2200 ± 130 km s-1. Similar waves propagating in opposite directions areobserved in closed loops between two flare ribbons. In the k-omega diagramof the Fourier wave power, we find a bright ridge that represents thedispersion relation and can be well fitted with a straight line passing throughthe origin. This k-omega ridge shows a broad frequency distribution withindicative power at 5.5, 14.5, and 25.1 mHz. The strongest signal at 5.5 mHz(period 181 s) temporally coincides with quasi-periodic pulsations of theflare, suggesting a common origin. The instantaneous wave energy flux of(0.1-2.6) imes 107 ergs/cm^2/s estimated at the coronal base is comparableto the steady-state heating requirement of active region loops.